Genus Erythromma Charpentier, 1840
brighteyes

Type species: Agrion najas Hansemann, 1823

Introduction

For an introduction to this genus, please refer to: Dijkstra, K.-D.B. & R. Lewington, 2006. Field guide to the Dragonflies of Britain and Europe. British Wildlife Publishing. 1-320.

Diagnosis

This genus includes two types of species, both with bright-eyed males, sharing the following diagnostic features: (1) male’s eyes are bright red or blue, not capped with black; thus, the top of the eyes contrasts with the black upperside of the head; (2) the postocular spots are reduced to narrow stripes, or are absent; (3) the black marking on S2 on males extends along the segment, from base to tip; (4) males have no blue on the upperside of S8, while S9-10 are all or largely blue; the ‘blue tail’ is therefore shorter and closer to the abdomen’s tip; (5) upper appendages of males are much longer than lowers, about as long as S10; (6) the wing tips, especially in the hindwing, are very densely veined, because numerous cells have been subdivided; the pterostigmas are rather long. Females have no vulvar spine, unlike Enallagma and Ischnura. The blue-bodied E. lindenii was formerly placed in the genus Cercion, but details of its DNA, behaviour, and larval and adult morphology show that it is an Erythromma. It is compared with other blue-and-black damselflies in the species text. The red-eyed Erythromma males are the only damselflies combining red eyes with blue markings on the body and an all-dark back of head. Their females have dark eyes, no postocular spots and the entire abdomen upperside is dark. Males of other blue-tailed damselflies (Coenagrion, Enallagma, Ischnura) do not have red eyes and usually have postocular spots. Most damselflies with red eyes (Ceriagrion, Pyrrhosoma) also have red bodies. The red-faced male of Pseudagrion sublacteum is likely to be found only in Africa. The combination of characters in Erythromma females may also be found in all-dark forms of Ceriagrion and Pyrrhosoma. These will often have traces of red and have differently configured black markings on the thorax; the legs of Ceriagrion have no black. If seen well, males of the two red-eyed species can be identified in the field by details of the blue pattern on the abdomen. [Adapted from Dijkstra & Lewington 2006]

Map citation: Clausnitzer, V., K.-D.B. Dijkstra, R. Koch, J.-P. Boudot, W.R.T. Darwall, J. Kipping, B. Samraoui, M.J. Samways, J.P. Simaika & F. Suhling, 2012. Focus on African Freshwaters: hotspots of dragonfly diversity and conservation concern. Frontiers in Ecology and the Environment 10: 129-134.


Reference

  • Dijkstra, K.-D.B., and Lewington, R. (2006). Field guide to the Dragonflies of Britain and Europe. British Wildlife Publishing, 1-320.

Citation: Dijkstra, K.-D.B (editor). African Dragonflies and Damselflies Online. http://addo.adu.org.za/ [2017-03-26].